I’ve seen those “wall snags” down at the big dam as well. In fact, when fishing there, it’s become one of my “goto” techniques! Minnows or leeches help a lot but on the north side of the dam, the ledge you fish from is a small eddy that will hold fish as they dart in and out of the exchange pools. Set the bait down and wait. If you don’t have something within 10 minutes, do something else for an hour or so and try it again. Sooner or later, the feeders show up and you’ll get your bite. I have yet to get any real lunkers (other than white bass) doing this but I’ve seen others produce enough to believe it can happen with a small percentage of consistency. And as always, a smorgasbord of species!